JP2008007870A - Polyester fine fiber and its fiber product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester fine fiber having excellent hygroscopicity and keeping characteristic good shape stability and heat resistance of polyester fibers. <P>SOLUTION: The polyester fine fiber is composed mainly of polyethylene terephthalate and has a fiber diameter of ≥50 nm and ≤800 nm, a strength of 1.5-6.0 cN/dtex, an elongation of 15-60% and a moisture absorption of ≥1.5% at 35°C and 95% relative humidity. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fine polyester fiber having excellent hygroscopicity and good shape stability and heat resistance. More specifically, it relates to highly hygroscopic polyester fine fibers that can be suitably used for clothing materials such as inner, pants and sports clothing, industrial material products, daily life material products, environmental material products, pharmaceutical and hygiene products. is there.

  Conventionally, polyester is excellent in heat resistance and chemical resistance, and is widely used for synthetic fibers, biaxially oriented tapes for video and audio, and transparent bottles as food containers. Synthetic fibers can be used for clothing fibers and industrial materials such as tire cords. In particular, clothing fibers have a large market share because of excellent wash and wear (W & W) properties and shape memory stability. However, polyester fibers are less hygroscopic than natural fibers such as wool and cotton, so they can be worn on the skin or close to the skin such as inner and sports clothing. And is inferior to natural fiber in terms of comfort.

  Therefore, conventionally, research for imparting hygroscopicity to polyester fibers has been performed. For example, a method of modifying the raw yarn and a method of imparting hygroscopicity in the post-processing stage are conceivable. In the former, a core-sheath type composite fiber having a thermoplastic resin as a core and a fiber-forming polyester resin as a sheath, wherein the thermoplastic resin forming the core is a polyether ester amide, and the core The core-sheath type composite fiber having a ratio of 5 to 30% by weight of the total weight of the composite fiber is disclosed in Patent Document 1, and a hygroscopic component (polyalkylene oxide obtained by reaction of polyalkylene oxide with polyol and aliphatic diisocyanate compound) Patent Document 2 proposes a polyester fiber composed of a modified product) and mainly a PPT (polypropylene terephthalate) polymer. However, since the moisture absorption rate of the core part is high during hot water treatment such as dyeing, there is a problem that the fiber surface is cracked or cracked due to a difference in water swelling between the core part and the sheath part, and the hygroscopic component flows out.

In addition, the latter includes graft polymerization of acrylic acid or methacrylic acid on polyester fibers and introducing carboxyl groups substituted with alkali metals into the fiber, or a large amount of amide compounds such as acrylamide. Is known and proposed in Patent Document 3. If the introduction amount of the carboxyl group substituted with the alkali metal is increased, the moisture absorption property is increased, and a moisture absorption property higher than that of cotton can be obtained. However, a fabric imparted with hygroscopicity by a post-processing method such as this method has a problem that dyeing spots are likely to occur because a large amount of hygroscopic components are present on the fiber surface.
JP-A-2-99612 JP 2000-96343 A JP 47-33192 A

  An object of the present invention is to overcome the above-mentioned problems, and to provide a fine polyester fiber having excellent hygroscopicity and good shape stability and heat resistance.

The present invention mainly comprises polyethylene terephthalate, fiber diameter of 50 nm to 800 nm, strength of 1.5 to 6.0 cN / dtex, elongation of 15 to 60%, and moisture absorption at 35 ° C. and 95% of 1. It is related with the polyester fine fiber characterized by being 5% or more.
Here, the polyester fine fiber preferably has an apparent crystal size of (010) plane in the fiber structure of 60 Å (angstrom) or more and an apparent crystal size of (100) plane of 45 Å or more.
The polyester fine fiber of the present invention comprises an easily soluble component having a high melt viscosity and an insoluble component having a low melt viscosity mainly composed of polyethylene terephthalate, the former being a sea component and the latter being an island component, and a spinning speed of 1,500 to After melt spinning at 6,000 m / min, the obtained sea-island type composite undrawn yarn is oriented and crystallized and stretched at a temperature of 60 to 220 ° C. to form a sea-island type composite fiber. By extraction and removal, the island component is obtained as fine fibers mainly composed of polyethylene terephthalate.
In the sea-island type composite fiber, the melt viscosity ratio (sea / island) of the sea component and the island component is 1.1 to 2.0, and the composite weight ratio (sea: island) of the sea component and the island component is 40: It is preferable that it is 60-5: 95.
The sea component of the sea-island type composite fiber is mainly copolymerized polyethylene terephthalate obtained by copolymerizing 6 to 12 mol% of 5-sodium sulfoisophthalic acid and 3 to 10 wt% of polyethylene glycol having a molecular weight of 4,000 to 12,000. What is made into a component is preferable.
Further, the sea component of the sea-island type composite fiber is polyamide, and those that are soluble in formic acid are also preferable.
Next, this invention relates to the textiles which consist of the above polyester fine fiber.
Here, specific examples of the fiber product include woven or knitted fabric, felt or non-woven fabric, or spun yarn made of braided yarn or short fiber.
Examples of the use of the textile product include clothing / interior products, industrial material products, life material products, environmental material products, and pharmaceutical / hygiene products.

  According to the present invention, it is possible to provide a fine polyester fiber having excellent hygroscopicity and good shape stability and heat resistance inherent in the polyester fiber.

The present invention is described in detail below.
The polyester fine fiber of the present invention has a spinning speed of 1,500 to 6, with an easily soluble component having a high melt viscosity and an insoluble component having a low melt viscosity mainly composed of polyethylene terephthalate as the sea component and the latter as the island component. After melt spinning at 1,000,000 m / min, the obtained sea-island type composite undrawn yarn is obtained by extracting and removing sea components from the sea-island type composite fiber obtained by orientation crystallization drawing at a temperature of 60 to 220 ° C.

  This polyester fiber has a fiber diameter of 50 nm to 800 nm, a strength of 1.5 to 6.0 cN / dtex, an elongation of 15 to 60%, and a moisture absorption rate of 1.5% or more at 35 ° C. and 95%. There is the biggest feature in being. Since the moisture absorption rate at 35 ° C. and 95% is 1.5% or more, the structure of the fiber has an apparent crystal size of (010) plane of 60 mm or more, and an apparent crystal of (100) plane. It is important that the size is 45 mm or more.

Here, the fiber diameter needs to be in the range of 50 to 800 nm, preferably 100 to 500 nm. By adjusting the fiber diameter to the above range, the strength of fine fibers having a diameter of 50 to 800 nm obtained by dissolving and removing sea components from the sea-island composite fiber of the present invention is 1.5 to 6.0 cN / dtex, preferably 2 The elongation can be 15 to 60%, preferably 20 to 40% at 0.5 to 5.0 cN / dtex.
In particular, it is important that the strength of the polyester fine fiber of the present invention is 1.5 cN / dtex or more. If the strength is lower than this, the desired fine fiber cannot be obtained.
Also, if the elongation is less than 15%, the fiber structure itself is unstable, and the physical properties and fiber form tend to be unstable, which is not preferable. On the other hand, if it exceeds 60%, the shape stability is deteriorated because of high shrinkage, which is not preferable.
Furthermore, the moisture absorption at 35 ° C. and 95% of the polyester fine fiber of the present invention is 1.5% or more, preferably 1.5 to 10%. If it is less than 1.5%, the hygroscopicity of the resulting fiber is poor, and the desired polyester fine fiber cannot be obtained.

  In the structure of the polyester fine fiber of the present invention, the apparent crystal size of the (010) plane is particularly preferably 60 mm or more, and the apparent crystal size of the (100) plane is preferably 45 mm or more. When the apparent crystal size of the (010) plane is less than 60 mm and the apparent crystal size of the (100) plane is less than 45 mm, the desired fine fiber with high moisture absorption cannot be obtained. Considering that the fiber is mainly composed of polyethylene terephthalate, the apparent crystal size of the (010) plane is preferably up to 85 mm, and the apparent crystal size of the (100) plane is preferably up to 90 mm.

  As the fibers become thinner, the apparent crystal size tends to increase, and the hygroscopicity increases by adopting this fiber structure. This is a phenomenon unique to nanofibers that has not been seen in the past. It has been found that by reducing the number of polymer aggregate units as much as possible by making the fibers finer, even with the same polyester material, it is possible to obtain performance improvements and new functions that have never been seen before. Incidentally, the fiber diameter of a general textile fiber is 20 μm, and the number of polymers composing it is 870 million. On the other hand, when the fiber diameter is 100 nm, it is composed of hundreds to thousands of polymers. ing.

  In order to obtain the above fibers, an easily soluble component having a high melt viscosity and an insoluble component having a low melt viscosity mainly composed of polyethylene terephthalate, the former being a sea component and the latter being an island component, the spinning speed is preferably After melt spinning at 1,500 to 6,000 m / min, the obtained sea-island type composite undrawn yarn is oriented and crystallized and stretched at a temperature of preferably 60 to 220 ° C. to form a sea-island type composite fiber. It is preferable to extract and remove the sea component from the composite fiber to obtain the island component as a fine fiber mainly composed of polyethylene terephthalate.

The polymer constituting the sea-island type composite fiber of the present invention is arbitrary as long as the sea component polymer is a combination having higher solubility than the island component polymer, but the dissolution rate ratio (sea / island) is preferably 500 or more. More preferably, it is 800 to 3,000. When the dissolution rate ratio is less than 500, part of the island component of the fiber cross-section surface layer is dissolved while the sea component of the fiber cross-section center is dissolved, so the sea component is completely dissolved and removed. For this reason, the island component is reduced by a percentage, and strength deterioration due to the thickness variation of the island component and solvent erosion occurs, and problems such as fluff and pilling are likely to occur.
Here, the dissolution rate is a 4% NaOH aqueous solution at 95 ° C., and the dissolution rate constant from the weight loss rate (insoluble weight fraction = 1−weight loss rate), treatment time, fiber radius, and calculate.

Here, k is a dissolution rate constant, R is an insoluble weight fraction, t is a treatment time, and r0 is a fiber radius.
The sea component polymer may be any polymer as long as the dissolution rate ratio with the island component is 500 or more, but fiber-forming polyester, polyamide, polystyrene, polyethylene, and the like are particularly preferable. For example, as an easily soluble polymer in an alkaline aqueous solution, polylactic acid, an ultra-high molecular weight polyalkylene oxide condensation polymer, a polyethylene glycol compound copolymer polyester, a copolymer polyester of polyethylene glycol compound and 5-sodium sulfonic acid isophthalic acid may be used. Is preferred.
Further, examples of the sea component polymer include polyamides such as nylon 6, nylon 66, nylon 612, nylon 11 and nylon 12, and polyamides such as nylon 6 and nylon 66 are particularly preferable. When the number of carbons in the repeating unit is smaller than that of nylon 6, for example, nylon 4, the interfacial energy is large, the affinity with copolymerized polyethylene naphthalate is insufficient, and thermal decomposition at high temperatures is likely to occur. It is not preferable. Polyamide is soluble in formic acid, and polystyrene and polyethylene are very soluble in organic solvents such as toluene.

  Among them, in order to achieve both easy alkali solubility and sea-island cross-sectional formability, the polymer mainly composed of polyethylene terephthalate has 6 to 12 mol% of 5-sodium sulfoisophthalic acid and a molecular weight of 1,000 to 12,000. A polyethylene terephthalate copolymer polyester having an intrinsic viscosity (measured in o-chlorophenol at 35 ° C.) of 0.4 to 0.6 dl / g obtained by copolymerizing 3 to 10% by weight of polyethylene glycol (PEG) is preferable. Here, 5-sodium isophthalic acid contributes to improving hydrophilicity and melt viscosity, and polyethylene glycol (PEG) improves hydrophilicity.

Here, when the copolymerization amount of 5-sodium sulfoisophthalic acid is less than 6 mol%, the dissolution rate with respect to the island is insufficient, and the intended fiber cannot be obtained. Since it becomes high and spinnability worsens, it is not preferable. The copolymerization amount of 5-sodium sulfoisophthalic acid is preferably 7 to 11 mol%.
In addition, when the molecular weight of PEG is less than 1,000, the heat resistance of the copolyester is lowered. On the other hand, when it exceeds 12,000, the effect of increasing hydrophilicity, which is considered to be due to the higher order structure, is increased. Since the reactivity becomes poor and a blend system is formed, it is not preferable from the viewpoints of heat resistance and spinning stability. Furthermore, if the copolymerization amount of PEG is less than 3% by weight, the alkali solubility is insufficient, and the target fiber cannot be obtained. On the other hand, if it exceeds 10% by weight, the melt viscosity is naturally reduced. It becomes difficult to achieve the object of the present invention. Therefore, it is preferable to copolymerize both components within the above range. The copolymerization amount of PEG is preferably 3 to 8% by weight.

On the other hand, the island component polymer has a difference in dissolution rate from the sea component, and polyester having a fiber-forming polyethylene terephthalate in a structural unit of 85 mol% or more is particularly preferable.
For example, in the present invention, the polyester used for the island component comprises 85 mol% or more of the acid component constituting terephthalic acid, and is selected from at least one glycol, preferably ethylene glycol, trimethylene glycol, tetramethylene glycol. it can. Such a polyester may contain a conventionally known copolymer component within a range that does not impair the object of the present invention. For example, the polyester has a range that does not impair the object of the present invention, preferably 15 mol%. Hereinafter, a conventionally known copolymer component may be contained within a range of 10 mol% or less, such as isophthalic acid, naphthalene dicarboxylic acid, diphenyldicarboxylic acid, diphenoxyethanedicarboxylic acid, β-hydroxyethoxy. Mention may be made of aromatic, aliphatic and alicyclic bifunctional carboxylic acids such as benzoic acid, ρ-oxybenzoic acid, 5-sodium sulfoisophthalic acid, adipic acid, sebacic acid, 1,4-cyclohexanedicarboxylic acid, etc. it can. Examples of diol compounds other than the above glycols include aliphatic, alicyclic and aromatic diol compounds such as cyclohexane-1,4-dimethanol, neopentyl glycol, bisphenol A and bisphenol S, and polyoxyalkylene glycol. I can give you. Further, if necessary, additives such as a matting agent, an antistatic agent, and a stabilizer can be appropriately included.

Such polyester may be synthesized by any method. For example, usually terephthalic acid and ethylene glycol are directly reacted with ester, terephthalic acid lower alkyl ester such as dimethyl terephthalate is transesterified with ethylene glycol, or terephthalic acid is reacted with ethylene oxide. Thus, a first stage reaction for producing a glycol ester of terephthalic acid and / or a low polymer thereof, and a polycondensation reaction are carried out until the desired polymerization degree is reached by pressurizing the reaction product of the first stage under reduced pressure. Produced by a two-step reaction.
The intrinsic viscosity (measured in o-chlorophenol at 35 ° C.) of the above polyethylene terephthalate is usually 0.4 to 0.8 dl / g, preferably 0.5 to 0.7 dl / g.

The sea-island composite fiber of the present invention comprising the sea component polymer and the island component polymer described above needs to have a melt viscosity of the sea component larger than that of the island component polymer during melt spinning. The melt viscosity ratio (sea / island) of the sea component and the island component is preferably 1.1 to 2, more preferably 1.2 to 1.8. In such a relationship, even if the composite weight ratio of the sea component is reduced to less than 40%, most of the island component is hardly joined to be different from the sea-island type composite fiber.
Here, the melt viscosity of the sea component polymer at 275 ° C. is usually 1,000 to 3,000 poise, preferably 1,200 to 2,500 poise.
In addition, the melt viscosity of the island component polymer at the same temperature is usually 500 to 3,000 poise, preferably 1,000 to 2,300 poise.

  In addition, as the number of islands increases, the productivity in the production of ultrafine fibers by dissolving and removing sea components increases, and the fineness of the resulting ultrafine fibers becomes remarkable, and the softness and smoothness unique to ultrafine fibers It is important that the glossiness is 100 or more, preferably 500 or more, because glossiness can be expressed. Here, when the number of islands is less than 100, even if the sea component is dissolved and removed, a high multifilament yarn composed of a single yarn having a very fineness cannot be obtained, and the object of the present invention cannot be achieved. If the number of islands is too large, not only the manufacturing cost of the spinneret increases, but also the processing accuracy itself tends to decrease.

  The sea-island composite fiber of the present invention preferably has a sea-island weight ratio (sea: island) in the range of 40:60 to 5:95, particularly preferably in the range of 30:70 to 10:90. Within such a range, the thickness of the sea component between the islands can be reduced, the sea component can be easily dissolved and removed, and the conversion of the island component into ultrafine fibers is facilitated. Here, when the proportion of the sea component exceeds 40%, the thickness of the sea component becomes too thick. On the other hand, when the proportion is less than 5%, the amount of the sea component becomes too small, and joining between islands is likely to occur. .

As the spinneret used for melt spinning, any one such as a hollow pin group for forming an island component or a group having a fine hole group can be used. For example, any spinneret that forms a cross section of the sea island by combining the island component extruded from the hollow pin or fine hole and the sea component flow that is designed to fill the gap between them is compressed. Good. Examples of spinnerets that are preferably used are shown in FIGS. 1 and 2, but are not necessarily limited thereto.
FIG. 1 shows a method in which hollow pins are discharged into a sea component resin reservoir portion and merged and compressed. FIG. 2 shows a method in which islands are formed by a fine hole method instead of hollow pins.

  The discharged sea-island type cross-section composite fiber is solidified by cooling air, and is preferably wound after being melt-spun at 1,500 to 6,000 m / min. More preferably, it is 2,000-3,500 m / min. If it is less than 1,500 m / min, the desired fine fiber cannot be obtained and the productivity is poor. On the other hand, if it exceeds 6,000 m / min, the spinning stability is poor.

The obtained undrawn yarn is made into a composite fiber having desired strength and elongation characteristics through a separate drawing process, or is taken up by a roller at a constant speed without being wound once, and subsequently passed through a drawing process. Any method of winding later may be used. Specifically, it is preheated on a preheating roller of 60 to 220 ° C., preferably 60 to 190 ° C., more preferably 75 ° C. to 180 ° C., and a draw ratio of 1.2 to 6.0 times, preferably 2.0 to It is preferable that the film is stretched at 5.0 times and heat set is performed at a set roller of 120 to 220 ° C, preferably 130 to 200 ° C. In the case where the preheating temperature is insufficient, the desired high-magnification stretching cannot be achieved. If the set temperature is too low, the shrinkage rate is too high, which is not preferable. On the other hand, if the set temperature is too high, the physical properties of the fibers are remarkably lowered.
The elongation of the sea-island composite fiber thus obtained is preferably 5 to 35%, more preferably 9 to 30%. Outside the above range, the desired fine fiber of the present invention cannot be obtained.
The strength of the sea-island type composite fiber used in the present invention is preferably 2.0 to 6.0 cN / dtex, more preferably 3.5 to 5.9 cN / dtex.
The strength and elongation of the sea-island type composite fiber can be adjusted by controlling conditions such as spinning, stretching temperature, and draw ratio.

The polyester fine fiber of the present invention is a fine fiber mainly composed of polyethylene terephthalate which is an island component by extracting and removing the sea component from the sea-island type composite fiber thus obtained.
In the present invention, in order to extract and remove the sea component from the sea-island type composite fiber, the sea-island type composite fiber itself or a fabric obtained by weaving or knitting the same is hydrolyzed to obtain the sea component. Is decomposed and removed to obtain fine fibers. As a method of treating with a hydrolyzing agent, a method of heat-treating in an aqueous solution of hydrolyzing agent is used. As the hydrolyzing agent, when the sea component is the above copolymerized polyester, there are alkali metal compounds such as sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate. Among them, sodium hydroxide is preferably used. The concentration and temperature of the aqueous alkali solution vary depending on the type of alkali compound used, but the concentration is preferably 10 to 300 g / l, the temperature is 40 ° C. to 180 ° C., and the treatment time is preferably 2 minutes to 20 hours.

  When the sea component is polyamide, the sea component is preferably extracted and removed with formic acid at 25 ° C. (room temperature), and the treatment time is preferably 5 minutes to 48 hours.

Hereinafter, the present invention will be described more specifically with reference to examples.
The polymers used in the examples are as shown in Table 1.

Each evaluation item was measured by the following method.
(1) Melt viscosity The polymer after drying treatment was set in an orifice set at 275 ° C and melted and held for 5 minutes, then extruded under several levels of load, and the shear rate and melt viscosity at that time were plotted. The plot was gently connected to create a shear rate-melt viscosity curve, and the melt viscosity at a shear rate of 1000 sec- ¹ was estimated.
(2) Island number A fiber cross-sectional photograph was taken with a transmission electron microscope TEM, and the number of islands was counted.

(3) Strength and elongation of sea-island type composite fiber The weight of sea-island type composite fiber 9,000 m was measured n = 3 times, and the fineness was determined from the average value. Then, a stress-elongation curve obtained at room temperature with an initial sample length = 200 mm and a pulling speed of 200 m / min was measured, and the strength and elongation were determined from the fiber breaking point.

(6) Strength / elongation of fine fiber Using a sea-island type composite fiber, a tubular knitting with a weight of 1 g or more is prepared, the sea components are dissolved and removed, and then the tubular knitting is unwound. A load-elongation curve was determined at a speed of 200 m / min. The fineness was measured according to the method described in JIS-1015. The strength was obtained by dividing the load value at break by the calculated fineness, and the elongation was obtained from the elongation value at break.

(7) Apparent crystal size Relyed on wide angle X-ray diffraction method. Using an X-ray generator (RAD-3A type) manufactured by Rigaku Denki Co., Ltd., the scattering intensity was measured with Cu-Kα rays monochromatized with a nickel filter, and the crystallinity was calculated by the following formula.
Crystallinity = Scattering intensity of crystal part / total scattering intensity × 100 (%)
The crystal size was calculated from the half width of the reflection using the Scherrer equation.
Scherrer's equation L = λ / β ₀ cosθ _B
L: Crystal size [Angstrom]
λ: X-ray wavelength (1.5418 angstroms)
θ _B : Bragg angle, β ₀ : (β _E ² −β _I ² ) ^1/2
β _E : Measured value of half width, β _I : Device constant (1.046 × 10 ^-2 )

(8) Hygroscopicity After measuring the absolute dry weight of a 1 g sample, it was placed in an artificial climate room at 35 ° C. and 95%, and the moisture content after 24 hours was determined.
(9) Fine fiber diameter (single yarn diameter)
A cylindrical braid having a weight of 1 g or more was prepared using sea-island type composite fibers, and after sea components were dissolved and removed, the surface was subjected to SEM observation, the fiber diameter was measured at 10 points, and the average value was calculated.

[Example 1]
PET1 is used as the island component, and modified PET2 is used as the sea component, and the sea component: island component is melted at a weight ratio of 30:70 using the spinneret shown in FIG. It was. The melt-discharged yarn could be stably wound at a winding speed of 3,000 m / min. The obtained undrawn yarn was subjected to roller drawing at a drawing temperature of 90 ° C. and a draw ratio of 2.8 times, and then heated and wound at 150 ° C. to obtain a drawn yarn of 11 dtex / 10 fil. The drawn yarn had an elongation of 4.0 cN / dtex and an elongation of 13.0%. The drawn yarn was circular knitted to prepare a knitted fabric, and then the weight was reduced by 30% at 95 ° C. with a 4% NaOH aqueous solution. Here, the difference in alkali weight loss of the sea-island component was 1,200 times. When the cross section of the fiber was observed, a uniform fine fiber group was formed, and the fiber diameter was 306 nm. When the physical properties of these fine fibers were measured, the strength was 3.1 cN / dtex and the elongation was 30.0%. After cutting this knitted fabric to about 1 g, the moisture absorption rate was measured at 95 ° C. and 35% to be 5%. The apparent crystal size of the (010) plane in the fiber structure was 65 mm, and the apparent crystal size of the (100) plane was 52 mm.

[Example 2]
PET1 is used for the island component, and modified PET1 is used for the sea component. The sea component: island component is melted and discharged at a weight ratio of 30:70 at a spinning temperature of 280 ° C. using the spinneret shown in FIG. It was. The melt-discharged yarn could be stably wound at a winding speed of 2500 m / min. The obtained undrawn yarn was roller-drawn at a drawing temperature of 90 ° C. and a draw ratio of 3.0 times, and then heat-set at 150 ° C. and wound to obtain a drawn yarn of 50 dtex / 10 fil. The drawn yarn had an elongation of 4.0 cN / dtex and an elongation of 22.5%. The drawn yarn was circular knitted to prepare a knitted fabric, and then the weight was reduced by 30% at 95 ° C. with a 4% NaOH aqueous solution. Here, the difference in alkali weight loss of the sea-island component was 1,200 times. When the cross section of the fiber was observed, a uniform fine fiber group was formed, and the fiber diameter was 460 nm. When the physical properties of these fine fibers were measured, the strength was 3.4 cN / dtex and the elongation was 40.4%. After cutting out this knitted fabric to about 1 g, the moisture absorption rate was measured at 95 ° C. and 35% and found to be 2%. The apparent crystal size of the (010) plane in the fiber structure was 60 mm, and the apparent crystal size of the (100) plane was 47 mm.

[Example 3]
PET1 is used for the island component, and modified PET2 is used for the sea component, and the sea component: island component is melted and discharged at a weight ratio of 20:80 at a spinning temperature of 280 ° C. using the spinneret shown in FIG. It was. The melt-discharged yarn could be stably wound at a winding speed of 1,500 m / min. The obtained undrawn yarn was roller-drawn at a drawing temperature of 90 ° C. and a draw ratio of 3.0 times, and then heat-set at 150 ° C. and wound to obtain a drawn yarn of 11 dtex / 10 fil. The drawn yarn had an elongation of 3.5 cN / dtex and an elongation of 17.4%. The drawn yarn was circular knitted to create a knitted fabric, and then the weight was reduced by 20% at 95 ° C. with a 4% NaOH aqueous solution. Here, the difference in alkali weight loss of the sea-island component was 1,200 times. When the cross section of the fiber was observed, a uniform fine fiber group was formed, and the fiber diameter was 470 nm. When the physical properties of these fine fibers were measured, the strength was 2.0 cN / dtex and the elongation was 43.6%. After cutting this knitted fabric to about 1 g, the moisture absorption rate was measured at 95 ° C. and 35% to be 7.5%. The apparent crystal size of the (010) plane in the fiber structure was 62 mm, and the apparent crystal size of the (100) plane was 50 mm.

Example 4
PET2 is used for the island component, Ny-6 is used for the sea component, and the sea component: island component is melted at a weight ratio of 40:60 using a spinneret shown in FIG. It was. The melt-discharged yarn could be stably wound at a winding speed of 2,000 m / min. The obtained undrawn yarn was roller-drawn at a drawing temperature of 90 ° C. and a draw ratio of 2.0 times, and then heat-set at 150 ° C. to obtain a drawn yarn of 5.5 dtex / 10 fil. The drawn yarn had an elongation of 3.5 cN / dtex and an elongation of 23.0%. The drawn yarn was circular knitted to create a knitted fabric, and then 40% sea components were dissolved with formic acid at room temperature. When the cross section of the fiber was observed, a uniform fine fiber group was formed, and the fiber diameter was 185 nm. When the physical properties of these fine fibers were measured, the strength was 1.9 cN / dtex and the elongation was 29.5%. After cutting this knitted fabric to about 1 g, the moisture absorption rate was measured at 95 ° C. and 35%, and it was 6.8%. The apparent crystal size of the (010) plane in the fiber structure was 70 mm, and the apparent crystal size of the (100) plane was 59 mm.

[Comparative Example 1]
Using the same polymer as in Example 1, the sea component: island component was melted and discharged at a spinning temperature of 280 ° C. using a spinneret shown in FIG. The melt-discharged yarn could be stably wound at a winding speed of 2500 m / min. The obtained undrawn yarn was roller-drawn at a drawing temperature of 90 ° C. and a draw ratio of 1.6 times, and then heat-set at 150 ° C. and wound to obtain a drawn yarn of 24.2 dtex / 10 fil. The elongation of the drawn yarn was 2.5 cN / dtex in strength and 38.9% in elongation. The drawn yarn was circularly knitted to prepare a knitted fabric, and then the weight was reduced 60% at 95 ° C. with 4% NaOH aqueous solution. Here, the difference in alkali weight loss of the sea-island component was 1,200 times. When the cross section of the fiber was observed, a uniform fine fiber group was formed, and the fiber diameter was 1.0 μm. When the physical properties of these fine fibers were measured, the strength was 1.4 cN / dtex and the elongation was 65.4%. After cutting this knitted fabric to about 1 g, the moisture absorption rate was measured at 95 ° C. and 35%, and it was as low as 0.7%. In addition, the apparent crystal size of the (010) plane in the fiber structure was 55Å, and the apparent crystal size of the (100) plane was 44Å and the crystal size was also small.

[Comparative Example 2]
Using the same polymer as in Example 1, the sea component: island component was melted and discharged at a spinning temperature of 280 ° C. using a spinneret shown in FIG. The melt-discharged yarn could be stably wound at a winding speed of 1,000 m / min. The obtained undrawn yarn was roller-drawn at a drawing temperature of 90 ° C. and a draw ratio of 4.6 times, and then heat-set at 150 ° C. and wound to obtain a drawn yarn of 44 dtex / 36 fil. The drawn yarn had an elongation of 5.4 cN / dtex and an elongation of 10.9%. The drawn yarn was circular knitted to prepare a knitted fabric, and then the weight was reduced by 30% at 95 ° C. with a 4% NaOH aqueous solution. Here, the alkali weight loss rate difference of the sea island component was 1200 times. When the cross section of the fiber was observed, a uniform fine fiber group was formed, and the fiber diameter was 2.5 μm. When the physical properties of these fine fibers were measured, the strength was 4.0 cN / dtex and the elongation was 31.4%. After cutting this knitted fabric to about 1 g and measuring the moisture absorption rate at 95 ° C. and 35%, it was as low as 0.5%. In addition, the apparent crystal size of the (010) plane in the fiber structure was 50 Å, and the apparent crystal size of the (100) plane was 41 Å, which was also small.

The polyester fine fiber of the present invention has a feature that the specific surface area is increased because it is a fine fiber. For this reason, it has excellent adsorption and absorption characteristics. Taking advantage of this effect, for example, a functional drug can be absorbed to develop a new application. As functional drugs, for example, drugs for promoting health and beauty such as proteins and vitamins, and other drugs such as anti-inflammatory agents and disinfectants can be used. On the other hand, it has not only absorption / adsorption characteristics but also excellent controlled release characteristics. Taking advantage of this effect, the above-mentioned functional drugs can be released, and can be deployed in various pharmaceutical and hygiene applications including drug delivery systems.
The fiber product containing at least a part of the polyester fine fiber of the present invention can be an intermediate product such as yarn, braided yarn, spun yarn composed of short fibers, woven fabric, knitted fabric, felt, non-woven fabric, and artificial leather. Here, “included in at least a part” means that 5% by weight or more, preferably 10% by weight or more of the fiber product is composed of the polyester fine fiber of the present invention.
In the present invention, these intermediate products are classified into clothing such as jackets, skirts, pants and underwear, sports clothing, clothing materials, interior products such as carpets, sofas and curtains, vehicle interior products such as car seats, cosmetics, cosmetic masks, Use for daily use such as wiping cloth and health supplies, environment and industrial materials such as abrasive cloths, filters, products for removing harmful substances, battery separators, and medical applications such as sutures, scaffolds, artificial blood vessels, blood filters, etc. Can do.

It is a cross-sectional block diagram of the spinneret of one Example for melt spinning the sea-island type composite fiber used for this invention. It is a cross-sectional block diagram of the spinneret of the other Example for melt-spinning the sea-island type composite fiber used for this invention.

Claims (10)

  Mainly composed of polyethylene terephthalate, fiber diameter of 50 nm to 800 nm, strength of 1.5 to 6.0 cN / dtex, elongation of 15 to 60%, and moisture absorption at 35 ° C. and 95% of 1.5% or more. Polyester fine fiber characterized by being.   The fine polyester fiber according to claim 1, wherein the apparent crystal size of the (010) plane in the fiber structure is 60 mm or more, and the apparent crystal size of the (100) plane is 45 mm or more.   Melt spinning at a spinning speed of 1,500 to 6,000 m / min with an easily soluble component having a high melt viscosity and an insoluble component having a low melt viscosity mainly composed of polyethylene terephthalate, the former as a sea component and the latter as an island component After that, the obtained sea-island type composite unstretched yarn is oriented, crystallized and stretched at a temperature of 60 to 220 ° C. to form a sea-island type composite fiber, and the sea component is extracted and removed from the sea-island type composite fiber. The polyester fine fiber according to claim 1 or 2, which is obtained as a fine fiber mainly composed of terephthalate.   The polyester fine fiber according to claim 3, wherein the elongation of the sea-island type composite fiber is 5% to 35%.   In the sea-island type composite fiber, the melt viscosity ratio (sea / island) of the sea component and the island component is 1.1 to 2.0, and the weight ratio (sea: island) of the sea component and the island component is 40:60 to 5 The polyester fine fiber according to claim 3 or 4, which is: 95.   The sea component of the sea-island type composite fiber is mainly composed of copolymerized polyethylene terephthalate obtained by copolymerizing 6 to 12 mol% of 5-sodium sulfoisophthalic acid and 3 to 10 wt% of polyethylene glycol having a molecular weight of 4,000 to 12,000. The polyester fine fiber in any one of Claims 3-5.   The polyester fine fiber according to any one of claims 3 to 5, wherein the sea component of the sea-island composite fiber is polyamide and is soluble in formic acid.   A fiber product comprising the polyester fine fiber according to claim 1.   The textile product according to claim 8, which is a woven or knitted fabric, felt or nonwoven fabric, or a spun yarn made of braided yarn or short fiber. The textile product according to claim 8, which is a clothing / interior product, an industrial material product, a living material product, an environmental material product, or a pharmaceutical / hygiene product.